This section is intended to provide a background or context to the disclosed embodiments that are recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Digital watermarks have been proposed and used for copyright protection of audio, video, images and other types of media. In a typical watermarking scenario an auxiliary information signal is hidden within a host content in such a way that it is substantially imperceptible, and at the same time, difficult to remove without damaging the host content. In some applications, the auxiliary information that is hidden within the host content is used to provide copy control for the host media content. For example, the detection of an embedded watermark that includes copy control information (CCI) (hereinafter referred to as a CCI watermark) may stop the playback of an unauthorized content.
In other applications, digital watermarks may be used to carry other information, such as the identity of the content itself, the content owner, the distribution channel, the content format, and the like. Typically such information is embedded into the content using watermarks that have a larger payload (hereinafter referred to as an Extended Payload (EP) watermark) than the CCI watermarks. For example, while a watermark payload of 8 bits may suffice for carrying CCI, an extended payload of, for example, 20 to 100 bits may be required to embed non-copy control information. In some applications, EP watermarks may have different performance and reliability requirements than CCI watermarks.
Historically, CCI and EP watermarks have been used for distinct applications and, therefore, have been developed and implemented separately often using distinct watermarking techniques. Independent embedding and extraction of such watermarks can, however, result in unwanted artifacts in the host content and result in additional penalties in terms of watermark robustness and computational complexity of embedding and extraction operations.